OM-D Exposure Inconsistency?

Discussion in 'Olympus Cameras' started by zpierce, Mar 17, 2013.

  1. zpierce

    zpierce Super Moderator

    661
    Sep 26, 2010
    Minneapolis, MN
    Zach
    What do people make of this? Noticed it on a number of shots in the gym where the background is consistent enough for it to jump out at me. These shots have identical exposure settings (part of a burst, they were locked anyways per the high speed burst limitation). Only difference is a bit of framing change. Notice the fairly dramatic change in the wall exposure / color.
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    <a href="http://www.flickr.com/photos/zachpierce/8564079837/" title="P3070138.jpg by zach.pierce, on Flickr"> 8564079837_7a59798acb_z. "480" height="640" alt="P3070138.jpg"></a>
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  2. Savas K

    Savas K Mu-43 Top Veteran

    784
    Jan 10, 2013
    Could be the prevailing light source in the gym. Some alternate colors at a fast pace too quick to see, except when a camera captures the difference.
     
  3. rklepper

    rklepper Mu-43 Top Veteran

    733
    Dec 19, 2012
    Iowa, USA
    Robert
    Those lights actually flicker and you just caught 2 different ones. It is completely normal and aggravating.
     
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  4. janneman

    janneman Mu-43 Veteran

    414
    Dec 6, 2012
    Netherlands
    Jan (John) Kusters
    Could it be you were in auto white balance?
     
  5. WasOM3user

    WasOM3user Mu-43 Veteran

    458
    Oct 20, 2012
    Lancashire, UK
    Paul
    It's the lights

    Some lights that seem on continuously to your eye are actually flashing/strobing at a high frequency.

    I can tell that the lights are on a three phase supply as is normal for sports facilities (which means one third of the lights will all be on, one third going off and one third starting up - this is to try and minimise the strobing effects on balls, pucks or other fast moving objects).

    If you look at the back wall you can see this effect on the colour balance on right hand side swaps with the one on the left between the two shots and you can see on the top middle of left hand wall a difference in intensity in the two shots.

    Look at the top of the ball - first shot light is mainly from the top left (on), shadow directly under the ball and the second more balance with perhaps the right hand side getting brighter (left going off?) shadow near the right foot of the player. I did note there is a larger difference in framing than I would have expected from a "burst" series.
     
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  6. rklepper

    rklepper Mu-43 Top Veteran

    733
    Dec 19, 2012
    Iowa, USA
    Robert
    Yes, we always referred to that as flicker, but cycle probably would be a better term. It was one of the things that made shooting indoor sports such a challenge when my kids were in school. You just have to pick and choose the useable shots.

     
  7. Mikefellh

    Mikefellh Mu-43 Top Veteran

    939
    Jun 7, 2012
    Toronto, Canada
    There's a lot more light sources in the second image than in the first.

    Also note that the right most bulb in the right image is glowing red.
     
  8. FrayAdjacent

    FrayAdjacent Mu-43 Regular

    183
    Dec 5, 2012
    Austin, TX
    M@
    Auto White Balance? ISO auto?

    SOMETHING had to have changed. Like Mike above me says, there are a couple more lights in the frame in the second image, but all else being equal that should have resulted in overexposure. It looks like it's maybe -1/3 or -2/3 in the second shot. Something changed.

    What mode was the camera in? What was set to Auto?
     
  9. David A

    David A Mu-43 All-Pro

    Sep 30, 2011
    Brisbane, Australia
    What metering mode?

    It could be related in part to the lights cycling but I suspect it's more due to the metering mode you used and the slightly different field of view, with a different number of lights visible in each frame.

    The meter is measuring light falling on all or part of the sensor. Because there are a different number of lights visible in each frame there is going to be a different amount of light falling on the sensor in each frame. I'd expect less variation in light measured if you were using spot meter mode since the spot is in the centre of the frame and there's little change there, but if you were using the normal meter mode or the centre weighted mode, both of which take into account the whole of the sensor, there will be a change in the amount of light measured and the exposure will change as a result.
     
  10. With_Eyes_Unclouded

    With_Eyes_Unclouded Mu-43 All-Pro

    Apr 17, 2012
    Vassilios
    This.

    I'm pretty sure this was on auto WB and matrix metering. It's very common (and a convincing argument for shooting RAW).
     
  11. dwig

    dwig Mu-43 Top Veteran

    623
    Jun 26, 2010
    Key West FL
    NO...

    ... more lights visible in the frame, but no additional light on the subject, leads to underexposure, just like what is seen in the OP's pix.

    It's quite likely that the light's fluctuations in both brightness and color as the AC power cycles has added to the issue. When shooting under multi-vapor lighting such as this some inconsistency is to be expected in both brightness and color anytime a shutter speed higher than 1/60th is used. The higher the shutter speed the greater the possible shift. The same goes for shooting under ordinary fluorescents, though "compact fluorescents" generally use high frequency electronic ballasts rather than 60Hz magnetic ballasts and won't show an error.
     
  12. FrayAdjacent

    FrayAdjacent Mu-43 Regular

    183
    Dec 5, 2012
    Austin, TX
    M@
    Oh yeah... the FL light phenomenon. That could definitely explain it, as all of the lights would be cycling at the same time, and the shutter caught a dark time.

    My original thought was something like this - He may have been in Aperture Priority, and the second shot showed more light so the metering changed, but undershot by a bit.

    The FL light thing works, too.
     
  13. Savas K

    Savas K Mu-43 Top Veteran

    784
    Jan 10, 2013
    What a pile-on for this question. All of us saying essentially the same thing, but in different ways. :)
     
  14. zpierce

    zpierce Super Moderator

    661
    Sep 26, 2010
    Minneapolis, MN
    Zach
    The lights definitely make sense, thanks a lot gang!

    I don't think it's the metering, because at the end of the day, if it were a metering issue one of the exposure values would have changed. They were identical (and locked) since it was in burst mode.
     
  15. Mikefellh

    Mikefellh Mu-43 Top Veteran

    939
    Jun 7, 2012
    Toronto, Canada
    Especially in this type ofsituation you should learn manual exposure and white balance.
     
  16. zpierce

    zpierce Super Moderator

    661
    Sep 26, 2010
    Minneapolis, MN
    Zach
    I was manually exposed and locked, hence my confusion why subsequent frames looked different :) Also did manual white balance with card as those lights are challenging.